通过胍基化核糖核酸酶A的质子磁共振波谱研究赖氨酸-41在核糖核酸酶A中的作用。
The role of lysine-41 in ribonuclease A studied by proton-magnetic-resonance spectroscopy of guanidinated ribonuclease A.
作者信息
Brown L R, Bradbury J H
出版信息
Eur J Biochem. 1976 Sep;68(1):227-35. doi: 10.1111/j.1432-1033.1976.tb10782.x.
Ribonuclease A has been guanidinated at the lysine residues and the nona-guanidinated and deca-guanidinated (fully substituted) products separated. In confirmation of an earlier report by Glick and Barnard (1970), it has been shown by chemical procedures that the former derivative is not reacted at lysine-41. Guanidination of lysine-41 to produce the fully substituted product causes loss of enzymic activity without any apparent change of conformation, as tested by conformational comparisons (using proton magnetic resonance spectroscopy) including (a) difference spectroscopy, evidence for the involvement of lysine-41 in a catalytic role in the enzyme. Dimethylation of lysine-41 of nona-guanidinated ribonuclease A produces sharp proton resonances which shifts as the dimethylamino group is titrated and allow the determination of an apparent pK of 8.8 for unsubstituted lysine-41.
核糖核酸酶A已在赖氨酸残基处进行胍基化反应，并分离出了非九胍基化和十胍基化（完全取代）产物。为证实Glick和Barnard（1970年）早期的一份报告，通过化学方法表明，前一种衍生物在赖氨酸-41处未发生反应。赖氨酸-41胍基化生成完全取代产物会导致酶活性丧失，而构象无明显变化，这是通过构象比较（使用质子磁共振波谱）测试得出的，包括（a）差示光谱法，证明赖氨酸-41在该酶的催化作用中发挥作用。非九胍基化核糖核酸酶A的赖氨酸-41进行二甲基化会产生尖锐的质子共振，随着二甲基氨基被滴定，该共振会发生位移，从而可以确定未取代的赖氨酸-41的表观pK值为8.8。
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